Characterization of bovine ileal epithelial cell line for lectin binding,susceptibility to enteric pathogens,and TLR mediated immune responses

In this study, primary and immortalized bovine intestinal epithelial cells (BIECs) were characterized for the expression of surface carbohydrate moieties. Primary BIEC-c4 cells showed staining greater than 90 % for 16 lectins but less than 50 % staining for four lectins. Immortalized BIECs showed significantly different lectin binding profile for few lectins compared to BIEC-c4 cells. BIEC-c4 cells were studied for infectivity to E. coli, Salmonella enterica, bovine rotavirus, bovine coronavirus, and bovine viral diarrhea virus. Bovine strain E. coli B41 adhered to BIEC-c4 cells and Salmonella strains S. Dublin and S. Mbandaka showed strong cell invasion. BIEC-c4 cells were susceptible to bovine rotavirus. LPS stimulation upregulated IL-10, IL-8, and IL-6 expression and Poly I:C upregulated TLR 8 and TLR 9 expression. This study provides important knowledge on the glycoconjugate expression profile of primary and immortalized BIECs and infectivity and immune responses of primary BIECs to bacterial and viral pathogens or ligands.     

Detect unique molecular structure associated with physiochemical properties in CDC varieties of oat grain with unique nutrient traits [Feed Type vs. Milling Type] in comparison with barley grain using advanced molecular spectroscopy as a non-destructive biological tool

The objective of this study was to determinate grain unique protein inherent molecular structure that are related physiochemical and nutrient profiles in CDC developed oat varieties [CDC Nasser (Feed Type) and CDC Seabiscuit (Milling Type)] grown in cool climate condition in western Canada in comparison with conventional barley variety of CDC Meredith as a control using advanced molecular spectroscopy. Multivariate analyses, including an agglomerative hierarchical cluster analysis (CLA) and principal component analysis (PCA), were performed to identify protein molecular structural differences among the grains. The results revealed that CDC Seabiscuit contained greater (P < 0.05) protein structural Amide I and II than CDC Nasser and CDC Meredith, while the greater (P < 0.005) structural Amide I to II area and height ratios was detected in CDC Meredith. New oat grains had greater (P < 0.05) β-sheet height than barley grains, however, there was no difference in α-helix to β-sheet ratio values among the varieties. In conclusion, CDC Nasser and CDC Meredith had no difference in protein molecular structural features, while CDC Seabiscuit contains different protein structural characteristics as compared to CDC Meredith grain. The molecular structure features are highly associated with physiochemical and nutrient profiles in grains, which indicate that it also affect nutrient utilization and availability.     

汽车变速器齿轮修形仿真分析

汽车变速器的关键部件齿轮因其加工和装配质量的影响,工作时容易引起振动噪声大及承载能力降低等问题,而齿轮修形是解决这些问题的有效方法,且成本较低。针对某款汽车变速器,利用Romax对齿轮进行修形分析。结果表明,修形后减小了齿轮的传动误差和最大接触应力,齿面载荷分布更加合理。有效改善了齿轮的传动性能,增加了齿轮寿命。     

Annual sex hormonal profiles, gonad development and age determination of the Mekong giant catfish (Pangasianodon gigas, Chevey)

Annual sex hormonal profiles, gonad development and age determination of 18 (13–14 kg body weight) and three (145–226 kg body weight) Mekong giant catfish (MGC) (Pangasianodon gigas, Chevey) reared in earthen ponds in Chiang Mai and from the Mekong River in Chiang Rai, Thailand, respectively, were investigated. The hormonal profiles were determined from blood samples of the fish by electrochemiluminescence immunoassay during May to August in 2000. The highest testosterone levels of 0.06 ng mL^?1 in both sexes and the highest oestradiol of 47.8 and 14.23 pg mL^?1 in females and males, respectively, were observed in May. The gonadosomatic index was found to be 0.07 for males and 0.38 for females from ponds in comparison with 2.27 for males and 8.29 for females from the Mekong River. Higher development stages of spermatocytes and oocytes of the cultured fish in May than in February and November were demonstrated. No mature germ cells were obtained from either the males or females, indicating no sexual maturity. The average age of fish was determined from the annual rings of the cross‐section of the pectoral fins by a stereomicroscope. The average age of fish in earthen pond determined from the annual ring was 8 years, which agreed with the actual culture records, while those from the Mekong River were 21 years. This information will be beneficial for the breeding programmes and conservation of the MGC.     

Chromosomal and Plasmid Diversity of Agrobacterium Strains Isolated from Ficus benjamina Tumors

Agrobacteria were previously isolated from tumors developing on branches and aerial and hypogeous roots of weeping fig plants in Italy and in The Netherlands. A representative group of 48 strains was analyzed by PCR–RFLP of 16S and 16S + IGS ribosomal regions, PCR–RFLP of six Ti plasmid (pTi) regions and characterized for plasmid content. Two groups of agrobacteria were separated by cluster analysis of PCR–RFLP profiles of rrs gene: seventeen strains were similar to the new species Agrobacterium larrymoorei, while the remaining strains were included within the agrobacterium biovar 1 group. Sixteen different plasmid profiles from one to five plasmids were observed. In addition, 21 ribotypes and 20 pTi structures were arranged in many different combinations, showing that fig agrobacteria were characterized by a wide heterogeneity. A general lack of correlation between strain ribotypes and plasmid content was observed.     

内毒素介导动物急性肾功能衰竭机理的试验研究

为了阐明内毒素介导急性肾功能衰竭的机理,观察了内毒素性肾功能衰竭家兔血液凝固性变化和肾脏的病理形态学变化。与对照组家兔比较,模型组家兔血小板计数和血浆纤维蛋白原含量极显著降低(P<0 01),出血时间、凝血时间、凝血酶原时间和白陶土部分凝血活酶生成时间显著或极显著延长(P<0 05,P<0 01)。另一方面,内毒素注射在全部模型组家兔导致了弥漫性血管内凝血,71.4%的肾小球中发现了微血栓,肾小球纤维素密度指数达60 6%。此外,96.2%的肾小管上皮细胞变性坏死,84.1%的肾小管中有管型形成。对照组家兔均未发现这些病理变化。上述试验结果揭示,内毒素引发了弥漫性血管内凝血,而肾小球毛细血管内广泛形成的微血栓阻断了肾小球毛细血管血流,从而导致肾小球滤过率降低,这是内毒素介导急性肾功能衰竭的首要机理。此外,肾小管上皮细胞的变性、坏死可损害其重吸收和分泌功能,管型形成可阻塞肾小管管腔并增大肾球囊内的压力,这些也都是在内毒素介导急性肾功能衰竭发生发展过程中起重要作用的因素。     

Branched‐chain amino acid ratios in low‐protein diets regulate the free amino acid profile and the expression of hepatic fatty acid metabolism‐related genes in growing pigs

Liver metabolism is affected by nutrients. The aim of this study was to explore the effects of low‐protein diets (17% crude protein, CP) supplemented with branched‐chain amino acids (BCAAs), including leucine (Leu), isoleucine (Ile) and valine (Val), on hepatic amino acid profile and lipid metabolism in growing pigs. The ratio of Leu : Ile : Val in all groups was 1 : 0.51 : 0.63 (20% crude protein, CP), 1 : 1 : 1 (17% CP), 1 : 0.75 : 0.75 (17% CP), 1 : 0.51 : 0.63 (17% CP) and 1 : 0.25 : 0.25 (17% CP) respectively. Results revealed that compared to the positive control group (1 : 0.51 : 0.63, 20% CP), the low‐protein diets significantly augmented the concentrations of most essential amino acids and non‐essential amino acids (p < .05), with the greatest values observed in the 1 : 0.25 : 0.25 group. Moreover, relative to the control, the low‐protein diets with the Leu : Ile : Val ratio ranging from 1 : 0.75 : 0.75 to 1 : 0.25 : 0.25 markedly downregulated the mRNA abundance of acetyl‐CoA carboxylase (ACC), lipoprotein lipase (LPL) and fatty acid‐binding protein 4 (FABP‐4) (p < .05), and upregulated the mRNA expression of hormone‐sensitive lipase (HSL), peroxisome proliferator‐activated receptor‐g coactivator‐1α (PGC‐1α), uncoupling protein 3 (UCP3) and liver carnitine palmitoyltransferase 1 (L‐CPT‐1) (p < .05). Therefore, our data suggest that protein‐restricted diets supplemented with optimal BCAA ratio, that is, 1 : 0.75 : 0.75–1 : 0.25 : 0.25, induce a shift from fatty acid synthesis to fatty acid oxidation in the liver of growing pigs. These effects may be associated with increased mitochondrial biogenesis.     

Evaluating the nutritive profile of three insect meals and their effects to replace soya bean in broiler diet

This study was conducted to evaluate the comparative effect of maggot meal, silkworm meal and mealworm as dietary protein source on the production performance and some aspects of meat quality in broilers. In this regard, maggot meal was reared on chicken offal and poultry waste. Silkworm meal was obtained from silk industry, while mealworm was developed through beetles rearing. A total of 120‐day‐old broiler chicks were randomly divided into four groups where soya bean meal (M0) was replaced with maggot meal (M1), silkworm meal (M2) and mealworm (M3) respectively. Each group was further divided into three replicates. The study was carried out for a period of 5 weeks. Diets containing mealworm significantly reduced overall feed consumption and resulted into higher weight gain (p < .05). Lowest feed conversion ratio (FCR) was recorded for birds fed with mealworm diet (p < .05). Tenderness and juiciness of meat were higher (p < .05) in M3 compared to the control and other treatments. Mortality did not vary between the control and the treated groups. Therefore, it is concluded that insect meal is rich in essential nutrients and could be successfully used in broiler ration without compromising acceptability. In the light of this study, mealworm is the best choice in broiler ration, in comparison with maggot and silkworm.     

Amino acid profiles of rumen undegradable protein: a comparison between forages including cereal straws and alfalfa and their respective total mixed rations

Optimizing the amino acid (AA) profile of rumen undegradable protein (RUP) can positively affect the amount of milk protein. This study was conducted to improve knowledge regarding the AA profile of rumen undegradable protein from corn stover, rice straw and alfalfa hay as well as the total mixed ratio diets (TMR) based on one of them as forage source [forage‐to‐concentrate ratio of 45:55 (30% of corn stover (CS), 30% of rice straw (RS), 23% of alfalfa hay (AH) and dry matter basis)]. The other ingredients in the three TMR diets were similar. The RUP of all the forages and diets was estimated by incubation for 16 hr in the rumen of three ruminally cannulated lactating cows. All residues were corrected for microbial colonization, which was necessary in determining the AA composition of RUP from feed samples using in situ method. Compared with their original AA composition, the AA pattern of forages and forage‐based diets changed drastically after rumen exposure. In addition, the extent of ruminal degradation of analysed AA was not constant among the forages. The greatest individual AA degradability of alfalfa hay and corn stover was Pro, but was His of rice straw. A remarkable difference was observed between microbial attachment corrected and uncorrected AA profiles of RUP, except for alfalfa hay and His in the three forages and TMR diets. The ruminal AA degradability of cereal straws was altered compared with alfalfa hay but not for the TMR diets. In summary, the AA composition of forages and TMR‐based diets changed significantly after ruminal exposure, indicating that the original AA profiles of the feed cannot represent its AA composition of RUP. The AA profile of RUP and ruminal AA degradability for corn stover and rice straw contributed to missing information in the field.     

卧式泵站直管式出水流道型线变化水力性能数值模拟

基于不可压缩流体的连续性方程和雷诺时均N-S方程,采用CFD技术对卧式泵站直管式出水流道进行数值模拟计算,通过改变出水流道型线,分析出水流道内部流动特性及水力损失影响。研究表明,出水流道当断面形状设计为圆变方,在平面方向和立面方向均逐渐扩大的形式时,流道内流态最好;将进水流道断面在平面方向设计为先扩散后平直,而在立面方向均匀扩大的形式时,流态较好;而将断面在立面与平面方向均设计成先扩散后平直时,出水流道流态最差。